[PATCH 1/2 RESEND] drm/vc4: Fulfill user BO creation requests from the kernel BO cache.

2017-03-01 Thread Eric Anholt
The from_cache flag was actually "the BO is invisible to userspace",
so we can repurpose it to just zero out a cached BO and return it to
userspace.

Improves wall time for a loop of 5 glsl-algebraic-add-add-1 by
-1.44989% +/- 0.862891% (n=28, 1 outlier removed from each that
appeared to be other system noise)

Note that there's an intel-gpu-tools test to check for the proper
zeroing behavior here, which we continue to pass.

Signed-off-by: Eric Anholt 
---
 drivers/gpu/drm/vc4/vc4_bo.c | 13 +++--
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index 7abcd9c5dbe2..e5c7aa935b4b 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -211,21 +211,22 @@ struct drm_gem_object *vc4_create_object(struct 
drm_device *dev, size_t size)
 }
 
 struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
-bool from_cache)
+bool allow_unzeroed)
 {
size_t size = roundup(unaligned_size, PAGE_SIZE);
struct vc4_dev *vc4 = to_vc4_dev(dev);
struct drm_gem_cma_object *cma_obj;
+   struct vc4_bo *bo;
 
if (size == 0)
return ERR_PTR(-EINVAL);
 
/* First, try to get a vc4_bo from the kernel BO cache. */
-   if (from_cache) {
-   struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
-
-   if (bo)
-   return bo;
+   bo = vc4_bo_get_from_cache(dev, size);
+   if (bo) {
+   if (!allow_unzeroed)
+   memset(bo->base.vaddr, 0, bo->base.base.size);
+   return bo;
}
 
cma_obj = drm_gem_cma_create(dev, size);
-- 
2.11.0

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Re: [PATCH 1/2 RESEND] drm/vc4: Fulfill user BO creation requests from the kernel BO cache.

2017-03-02 Thread Boris Brezillon
On Wed,  1 Mar 2017 10:56:01 -0800
Eric Anholt  wrote:

> The from_cache flag was actually "the BO is invisible to userspace",
> so we can repurpose it to just zero out a cached BO and return it to
> userspace.
> 
> Improves wall time for a loop of 5 glsl-algebraic-add-add-1 by
> -1.44989% +/- 0.862891% (n=28, 1 outlier removed from each that
> appeared to be other system noise)
> 
> Note that there's an intel-gpu-tools test to check for the proper
> zeroing behavior here, which we continue to pass.
> 
> Signed-off-by: Eric Anholt 

Reviewed-by: Boris Brezillon 

> ---
>  drivers/gpu/drm/vc4/vc4_bo.c | 13 +++--
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
> index 7abcd9c5dbe2..e5c7aa935b4b 100644
> --- a/drivers/gpu/drm/vc4/vc4_bo.c
> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
> @@ -211,21 +211,22 @@ struct drm_gem_object *vc4_create_object(struct 
> drm_device *dev, size_t size)
>  }
>  
>  struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
> -  bool from_cache)
> +  bool allow_unzeroed)
>  {
>   size_t size = roundup(unaligned_size, PAGE_SIZE);
>   struct vc4_dev *vc4 = to_vc4_dev(dev);
>   struct drm_gem_cma_object *cma_obj;
> + struct vc4_bo *bo;
>  
>   if (size == 0)
>   return ERR_PTR(-EINVAL);
>  
>   /* First, try to get a vc4_bo from the kernel BO cache. */
> - if (from_cache) {
> - struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
> -
> - if (bo)
> - return bo;
> + bo = vc4_bo_get_from_cache(dev, size);
> + if (bo) {
> + if (!allow_unzeroed)
> + memset(bo->base.vaddr, 0, bo->base.base.size);
> + return bo;
>   }
>  
>   cma_obj = drm_gem_cma_create(dev, size);

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